Improvement of wave loads predictions by the 3D time-domain computer program SEALOADS

Enhancement for the computer code SEALOADS version 1.0 was carried out and a new version 1.1 was produced. The mathematical model and the codes of SEALOADS version 1.0 were carefully examined for ways to improve the prediction of sea loads. A new algorithm has been developed to account for the effect of variable added-mass, damping and restoring coefficients on ship motions. A validation study for version 1.1 was conducted for the case of a frigate at the Froude number 0.12. Results were compared with those from PRECAL and SHIPMO7 as well as the experimental data. A total-factor-error analysis was also carried out using two wave spectra - ITTC and JONSWAP. The computed results show an improvement in the sea loads prediction.